#include <stdio.h>
#include <unistd.h>

int main()
{
    pid_t id = fork();
    if(id < 0)
    {
        perror("fork\n");
    }
    else if(id == 0) 
    {
        //child process
        while(1)
        {
            printf("I am child, pid:%d, ppid:%d\n", getpid(), getppid());
            sleep(1);
        }
    }
    else 
    {
        //father process
        while(1)
        {
            printf("I am father, pid:%d, ppid:%d\n", getpid(), getppid());
            sleep(1);
        }
    }
    return 0;
}
